Image data compression is concerned with minimizing the number of bits required to represent an image. Some of the well-known methods are in the areas of pixel coding, predictive coding and transform coding.
Although image compression methods or systems exploit redundancy in the image data and attempt to pack large amount of information into a small number of samples, they often lack the intelligence to determine which object in a particular image needs to be displayed clearly. Such intelligence is important in today's commonly used audiovisual conferencing systems due to these systems' inherent cost and bandwidth constraints. More specifically, many of the audiovisual conferencing systems are based on International Telecommunication Union (ITU) standards such as H.320, published in March, 1993, H.324, published in January, 1996 or H.323, published May, 1996 and thrive on being affordable and operable on a personal computer systems. Consequently, the video compression and decompression schemes in these standards do not require as intensive computation and elaborate buffering mechanism as other more advanced image compression methods. Thus, the resulting images are often not distinctly sharp. Moreover, the line speeds to these said conferencing systems often range in the 20 kps to 384 kps. Because of the limited number of data bits available for compressing and transmitting video information, the processed images frequently lack clarity and suffer low frame rates.
Low image quality has hampered the uses of these conferencing systems. For example, a patent attorney may have trouble seeing drawings on a scientist's white board through an audiovisual conference. Similarly, a telecommuter may have trouble viewing the agenda being displayed on the conference room's projector screen. In order to overcome these problems without violating the same aforementioned cost and bandwidth constraints, an apparatus and method is needed to allow an user to select a region-of-interest and display said region with as much clarity as possible under the circumstances.